title: Production of superoxide in chloroplast thylakoid membranes ESR study with cyclic hydroxylamines of different lipophilicity.
abstract: Accumulation of nitroxide radicals, DCP· or TMT·, under illumination of a thylakoid suspension containing either hydrophilic, DCP-H, or lipophilic, TMT-H, cyclic hydroxylamines that have high rate constants of the reaction with superoxide radicals, was measured using ESR. A slower accumulation of TMT· in contrast with DCP· accumulation was explained by re-reduction of TMT· by the carriers of the photosynthetic electron transport chain within the membrane. Superoxide dismutase suppressed TMT· accumulation to a lesser extent than DCP· accumulation. The data are interpreted as evidencing the production of intramembrane superoxide in thylakoids.
authors.affiliation: Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia.
authors.forename: Marina
authors.initials: M
authors.lastname: Kozuleva
authors.forename: Irina
authors.initials: I
authors.lastname: Klenina
authors.forename: Ivan
authors.initials: I
authors.lastname: Proskuryakov
authors.forename: Igor
authors.initials: I
authors.lastname: Kirilyuk
authors.forename: Boris
authors.initials: B
authors.lastname: Ivanov
mesh_terms: D002021:Buffers; D002264:Carboxylic Acids / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D019811:Hydroxylamine / Q000737:chemistry* / Q000378:metabolism*; D018532:Pisum sativum / Q000166:cytology; D010710:Phosphates / Q000737:chemistry; D010880:Piperidines / Q000737:chemistry; D013481:Superoxides / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D002021:Buffers; D002264:Carboxylic Acids; D010710:Phosphates; D010880:Piperidines; D013481:Superoxides; D019811:Hydroxylamine